Return type and the number and types its arguments
UMBC CMSC 331 Final Examination, 16 December, 2004 1.General multiple-choice questions (30) |
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1.4 The Unix YACC program parses input using a (a) recursive descent parser; (b) a top-down parser; (c) an RR(1) parser; (d) a bottom-up shift reduce parser. (D)
1.5 The main difference between a sentence and a sentential form is (a) there is no difference; (b) a sentence contains only terminal symbols but a sentential form can contain some non-terminal symbols; (c) sentential forms are a subset of sentences but the converse is not true; (d) sentential forms have no handles but a sentence does. (B)
1.10 LISP macros are primarily used to define: (a) dynamically scoped environments; (b) closures; (c) functions that don’t evaluate all of their arguments; (d) reflective programs. (C)
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(b) S → ε | ab | ba | aSb | bSa
Stings with a prefix consisting of some number of a’s and b’s in
any order followed by a postfix formed by reversing the prefix and
changing each a to a b and each b to an a. The grammar is ambiguous,
since there are two ways to derive the sentence “ab”: S(s,b) and
S(a,S(e),b).
(c) S → aSb | C C → ε | c | Cc
Strings consisting of N a’s (N≥0) followed by any number of c’s
followed by N b’s. The grammar is ambiguous since there are two ways to
derive the sentence “cc”: S(C(C(c),c)) and
S(C(C(C(e),c),c)).
[T][F]: Methods declared in an interface are automatically public. [T]
[T][F]: Overloading and overriding refer the same thing in Java [F]
[T][F]: Instance variables defined by a class are always given initial values when an instance of the class is
created. [T]
[T][F]: Static methods do not require an instance of the class; they can be accessed through the class name. [T]
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4. Java class variables (5)
If we construct an object of type Foo, where class Foo { int x = 5; int y; Foo() { x = 2; } }, what are the values of x and y in the new object?
| (cons (cons (cons ‘a nil) (cons ‘b nil)) (cons ‘c nil)) |
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5.2 Give a LISP expression using only the LIST function that will create this list.
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| (list (list (list ‘a) b) ‘c) |
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| symbol | s-expression to return the symbol |
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| A | (car (car (car x))) |
| B | (car (cdr (car x))) |
| C | (car (cdr x)) |
((AGE 20) (MAJOR “CMSC”)(COURSES (CMSC331 CMSC311 BIOL340))
(6a) Write a function ASSOC that takes two arguments, a symbol and an ALIST, and returns the item associated with that symbol (if any) in the ALIST or NIL if there is no item associated with the symbol. E.g.:
If we just return the s-expression associated with a symbol, then getting back NIL from ASSOC would be ambiguous. Was the item not found, or was it found but the associated s-expression was NIL? For example, if AL is ((TALL T) (YOUNG NIL)(HAPPY T)) consider what would be returned by (ASSOC ‘YOUNG AL) versus (ASSOC ‘RICH AL).
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| What would be printed? | |
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| V0 | (A B) |
| V1 | (A A) |
| V2 | ((A) (A)) |
| V3 | ((A) A) |
| V4 | (((A) A) (A) A) |
(A B C)
| A | B | C |
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(A (B) ((C)))
UMBC CMSC 331 Final Examination, 16 December, 2004 8. Functional programming I (20: 10/10) |
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(DEFUN MAXINT (L) (MAXINT1 L 0)) (DEFUN MAXINT1 (L N) |
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(8b) Now write a version that uses the function reduce discussed in class and shown to the right. Hint: MAXINT should be a one liner that just calls REDUCE. Consider using the built in function MAX that takes two numbers and returns the larger.
(DEFUN MAXINT1 (L) (REDUCE L #’MAX 0))
9.4 What will the following expression return?
(MAPCAR (XYZZY (LAMBDA (X)(+ X 3)) (LAMBDA (X)(* X X))) '(1 2 3 4 5 6)) (4 7 12 19 28 39)
